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Posted on 2012-05-19 13:19 IceWee 閱讀(30899) 評論(3) 編輯 收藏 所屬分類: Java 、 加解密
本工具類經過測試可用，之前寫的沒有使用CipherInputStream和CipherOutputStream，生成的加密文件與源文件大小不一致，加密時沒有問題，解密時總是拋出如下異常：  Exception in thread "main" javax.crypto.BadPaddingException: Given final block not properly padded
at com.sun.crypto.provider.SunJCE_f.b(DashoA13*..)
at com.sun.crypto.provider.SunJCE_f.b(DashoA13*..)
at com.sun.crypto.provider.AESCipher.engineDoFinal(DashoA13*..)
at javax.crypto.Cipher.doFinal(DashoA13*..)其中BASE64底層依賴庫沒有使用SUN的，而是下載的“javabase64-1.3.1.jar” DESUtils.java package demo.security;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.security.Key;
import java.security.SecureRandom;
import javax.crypto.Cipher;
import javax.crypto.CipherInputStream;
import javax.crypto.CipherOutputStream;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
  /** *//**
 * <p>
* DES加密解密工具包
* </p>
*
* @author IceWee
* @date 2012-5-19
* @version 1.0
 */
public class DESUtils  {
private static final String ALGORITHM = "DES";
private static final int CACHE_SIZE = 1024;
  /** *//**
* <p>
* 生成隨機密鑰
* </p>
*
* @return
* @throws Exception
 */
public static String getSecretKey() throws Exception {
return getSecretKey(null);
}
/** *//**
* <p>
* 生成密鑰
* </p>
*
* @param seed 密鑰種子
* @return
* @throws Exception
*/
public static String getSecretKey(String seed) throws Exception {
SecureRandom secureRandom;
if (seed != null && !"".equals(seed))
secureRandom = new SecureRandom(seed.getBytes());
else
secureRandom = new SecureRandom();
KeyGenerator keyGenerator = KeyGenerator.getInstance(ALGORITHM);
keyGenerator.init(secureRandom);
SecretKey secretKey = keyGenerator.generateKey();
return Base64Utils.encode(secretKey.getEncoded());
}
/** *//**
* <p>
* 加密
* </p>
*
* @param data
* @param key
* @return
* @throws Exception
*/
public static byte[] encrypt(byte[] data, String key) throws Exception {
Key k = toKey(Base64Utils.decode(key));
Cipher cipher = Cipher.getInstance(ALGORITHM);
cipher.init(Cipher.ENCRYPT_MODE, k);
return cipher.doFinal(data);
}
/** *//**
* <p>
* 文件加密
* </p>
*
* @param key
* @param sourceFilePath
* @param destFilePath
* @throws Exception
*/
public static void encryptFile(String key, String sourceFilePath, String destFilePath) throws Exception {
File sourceFile = new File(sourceFilePath);
File destFile = new File(destFilePath);
if (sourceFile.exists() && sourceFile.isFile()) {
if (!destFile.getParentFile().exists()) {
destFile.getParentFile().mkdirs();
}
destFile.createNewFile();
InputStream in = new FileInputStream(sourceFile);
OutputStream out = new FileOutputStream(destFile);
Key k = toKey(Base64Utils.decode(key));
Cipher cipher = Cipher.getInstance(ALGORITHM);
cipher.init(Cipher.ENCRYPT_MODE, k);
CipherInputStream cin = new CipherInputStream(in, cipher);
byte[] cache = new byte[CACHE_SIZE];
int nRead = 0;
while ((nRead = cin.read(cache)) != -1) {
out.write(cache, 0, nRead);
out.flush();
}
out.close();
cin.close();
in.close();
}
}
/** *//**
* <p>
* 解密
* </p>
*
* @param data
* @param key
* @return
* @throws Exception
*/
public static byte[] decrypt(byte[] data, String key) throws Exception {
Key k = toKey(Base64Utils.decode(key));
Cipher cipher = Cipher.getInstance(ALGORITHM);
cipher.init(Cipher.DECRYPT_MODE, k);
return cipher.doFinal(data);
}
/** *//**
* <p>
* 文件解密
* </p>
*
* @param key
* @param sourceFilePath
* @param destFilePath
* @throws Exception
*/
public static void decryptFile(String key, String sourceFilePath, String destFilePath) throws Exception {
File sourceFile = new File(sourceFilePath);
File destFile = new File(destFilePath);
if (sourceFile.exists() && sourceFile.isFile()) {
if (!destFile.getParentFile().exists()) {
destFile.getParentFile().mkdirs();
}
destFile.createNewFile();
InputStream in = new FileInputStream(sourceFile);
OutputStream out = new FileOutputStream(destFile);
Key k = toKey(Base64Utils.decode(key));
Cipher cipher = Cipher.getInstance(ALGORITHM);
cipher.init(Cipher.DECRYPT_MODE, k);
CipherOutputStream cout = new CipherOutputStream(out, cipher);
byte[] cache = new byte[CACHE_SIZE];
int nRead = 0;
while ((nRead = in.read(cache)) != -1) {
cout.write(cache, 0, nRead);
cout.flush();
}
cout.close();
out.close();
in.close();
}
}
/** *//**
* <p>
* 轉換密鑰
* </p>
*
* @param key
* @return
* @throws Exception
*/
private static Key toKey(byte[] key) throws Exception {
DESKeySpec dks = new DESKeySpec(key);
SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(ALGORITHM);
SecretKey secretKey = keyFactory.generateSecret(dks);
return secretKey;
}
}
Base64Utils.java  package demo.security;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import it.sauronsoftware.base64.Base64;
  /** *//**
 * <p>
* BASE64編碼解碼工具包
* </p>
* <p>
* 依賴javabase64-1.3.1.jar
* </p>
*
* @author IceWee
* @date 2012-5-19
* @version 1.0
 */
public class Base64Utils {
  /** *//**
* 文件讀取緩沖區大小
 */
private static final int CACHE_SIZE = 1024;
/** *//**
* <p>
* BASE64字符串解碼為二進制數據
* </p>
*
* @param base64
* @return
* @throws Exception
*/
public static byte[] decode(String base64) throws Exception {
return Base64.decode(base64.getBytes());
}
/** *//**
* <p>
* 二進制數據編碼為BASE64字符串
* </p>
*
* @param bytes
* @return
* @throws Exception
*/
public static String encode(byte[] bytes) throws Exception {
return new String(Base64.encode(bytes));
}
/** *//**
* <p>
* 將文件編碼為BASE64字符串
* </p>
* <p>
* 大文件慎用，可能會導致內存溢出
* </p>
*
* @param filePath 文件絕對路徑
* @return
* @throws Exception
*/
public static String encodeFile(String filePath) throws Exception {
byte[] bytes = fileToByte(filePath);
return encode(bytes);
}
/** *//**
* <p>
* BASE64字符串轉回文件
* </p>
*
* @param filePath 文件絕對路徑
* @param base64 編碼字符串
* @throws Exception
*/
public static void decodeToFile(String filePath, String base64) throws Exception {
byte[] bytes = decode(base64);
byteArrayToFile(bytes, filePath);
}
/** *//**
* <p>
* 文件轉換為二進制數組
* </p>
*
* @param filePath 文件路徑
* @return
* @throws Exception
*/
public static byte[] fileToByte(String filePath) throws Exception {
byte[] data = new byte[0];
File file = new File(filePath);
if (file.exists()) {
FileInputStream in = new FileInputStream(file);
ByteArrayOutputStream out = new ByteArrayOutputStream(2048);
byte[] cache = new byte[CACHE_SIZE];
int nRead = 0;
while ((nRead = in.read(cache)) != -1) {
out.write(cache, 0, nRead);
out.flush();
}
out.close();
in.close();
data = out.toByteArray();
}
return data;
}
/** *//**
* <p>
* 二進制數據寫文件
* </p>
*
* @param bytes 二進制數據
* @param filePath 文件生成目錄
*/
public static void byteArrayToFile(byte[] bytes, String filePath) throws Exception {
InputStream in = new ByteArrayInputStream(bytes);
File destFile = new File(filePath);
if (!destFile.getParentFile().exists()) {
destFile.getParentFile().mkdirs();
}
destFile.createNewFile();
OutputStream out = new FileOutputStream(destFile);
byte[] cache = new byte[CACHE_SIZE];
int nRead = 0;
while ((nRead = in.read(cache)) != -1) {
out.write(cache, 0, nRead);
out.flush();
}
out.close();
in.close();
}
}
DESTester.java package demo.security;
public class DESTester {
static String key;
static {
try {
key = DESUtils.getSecretKey();
} catch (Exception e) {
e.printStackTrace();
}
}
public static void main(String[] args) throws Exception {
long begin = System.currentTimeMillis();
encryptFile();
decryptFile();
test();
long end = System.currentTimeMillis();
System.err.println("耗時：" + (end-begin)/1000 + "秒");
}
static void encryptFile() throws Exception {
String sourceFilePath = "D:/demo.mp4";
String destFilePath = "D:/demo_encrypted.mp4";
DESUtils.encryptFile(key, sourceFilePath, destFilePath);
}
static void decryptFile() throws Exception {
String sourceFilePath = "D:/demo_encrypted.mp4";
String destFilePath = "D:/demo_decrypted.mp4";
DESUtils.decryptFile(key, sourceFilePath, destFilePath);
}
static void test() throws Exception {
String source = "這是一行測試DES加密/解密的文字，你看完也等于沒看，是不是啊？！";
System.err.println("原文:\t" + source);
byte[] inputData = source.getBytes();
inputData = DESUtils.encrypt(inputData, key);
System.err.println("加密后:\t" + Base64Utils.encode(inputData));
byte[] outputData = DESUtils.decrypt(inputData, key);
String outputStr = new String(outputData);
System.err.println("解密后:\t" + outputStr);
}
}
Feedback
# re: Java DES文件加密解密 javax.crypto.BadPaddingException: Given final block not properly padded 回復 更多評論
2012-09-04 22:09 by
str.getBytes();
調用此方法時，凡是未指定具體字符編碼的程序，均依賴于JRE所在操作系統的默認編碼類型，因此類似的加解密程序均是不完全可靠的。解決辦法：調用此方法時指定為 UTF-8 編碼，即：str.getBytes("UTF-8");
# re: Java DES文件加密解密 javax.crypto.BadPaddingException: Given final block not properly padded 回復 更多評論
2012-09-05 09:07 by
@yaray
感謝回復，可能我系統上的文字都用的UTF-8編碼吧，Eclipse的編碼也用的UTF-8，所以沒有測試到這個bug。
# re: Java DES文件加密解密 javax.crypto.BadPaddingException: Given final block not properly padded 回復 更多評論
2013-01-10 20:34 by
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